I. Field of the Invention
The present invention relates to a method of making a continuous belt of individually sealed containers and the belt formed thereby. The present invention includes first sealing the individual containers, before placing the sealed containers into separate compartments or cells in the belt.
II. Description of the Prior Art
Aerosols are suspensions of solid particles dispersed in the air. Aerosols are used in the military to defensively position and protect combat forces. In civilian use, aerosol dispersal is used by police for riot control and by farmers for agricultural purposes. These solid particle payloads have included smokes, obscurants, riot control agents, insecticides, pesticides, fungicides, fertilizer, feed and other similar compounds.
The military has used a multitude of devices ranging from pneumatic spray tanks to high explosive (HE) grenades to disperse a variety of solid particle payloads into the atmosphere. During military operations, a military force may be targeted by visual means, ultraviolet, infrared (IR), and millimeter (mm) radar sensors. In countering this targeting, various types of filler payloads are used for aerosol dissemination. These payloads include carbon fiber payloads to block energy in the mm region of the electromagnetic spectrum, smokes to obscure military forces from visual detection, and brass flakes or graphite flakes which interfere with IR tracking and target acquisition devices.
Current military IR dispersion techniques require that military personnel load IR material from bulk bag containers. Personnel physically remove the filler material from large bags and place the filler into a separate hopper for dispersion. Generally, the filler is dirty to handle. The particles also may create hazardous toxic atmospheric dust during the loading phase, presenting a health risk to the personnel handling the filler. Typically, the materials include fillers such as pelletized graphite shipped in 30 pound bags.
In civilian use, aerosols are dispersed by police as a non-lethal means for crowd dispersal, riot control, personal protectants and/or incapacitating agents. Additionally, aerosols used for civilian commercial purposes include the dispersal of aerosols for agricultural uses, such as disseminating insecticides, pesticides, fertilizers or feed over a wide area. The dispersal of aerosol particles for both military and civilian use should have safe handling and activation characteristics.
U.S. Pat. Nos. 6,076,671 and 6,170,234, both of which are hereby incorporated by reference in their entireties, describe a typical solid particle aerosol belt and methods for disseminating the contents of such belts.
However, conventional particle aerosol belts have various shortcomings. The most significant of these is due to the design of the belt itself. The basic design of known belts incorporate a heat seal, running the length of the belt.
Studies of such conventional heat sealed belts revealed the contamination of the heat seal surface by the contents of the belt, such as brass flake. This contamination often causes the heat seal to become ineffectual preventing the complete adherence of the surfaces.
Accordingly, zipper sealed belts were developed. In such belts, the heat seals, entrapping the brass flake or other material in the individual cells were replaced by standard zipper lock systems. The surface of the belt exiting beyond the zipper lock was thoroughly cleaned once the flakes were inserted into the cells, to allow heat sealing of the belt surface.
This two-seal system presented other disadvantages. First, excessive manual labor to clean the belt to permit effective heat seals is required. Additionally, because of the zipper lock, the heat seal used to separate the individual cells cannot extend completely across the face of the belt. This leaves a passageway connecting the cells, allowing the materials contained therein to xe2x80x9cleakxe2x80x9d from cell to cell. Therefore, if a belt were partially used, such as described by U.S. Pat. No. 6,076,617, the material contained in the unused cells could exit the cells and enter the atmosphere through these continuous passageways. The result would often include loss of material, contamination of packaging and surrounding surfaces, as well as inferior performance.
Additionally, the conventional process of filling a particle aerosol belt is a dry fill method. However, the present inventors learned that it is not practical to simply dispense dry particulate matter into the containers having an opening with a zip-type fastener such as a ZIP LOCK fastener used in the present invention, as such a dry fill process presented difficulties in maximizing packing density and minimizing contamination of the brass flake onto outer surfaces of either the zip-fastener type containers or the belt itself. No dry filling technique, including pressurized syringe filling, pouring or metering pumping solved the problem. Additionally, after subjecting the cells to a vacuum to remove air from the cells, it has shown to be nearly impossible to transfer the filled and evacuated cells to another work station for sealing without reintroducing air back into the cells.
The present invention is a double-seal system for particle aerosol belts, which overcomes the problems of the conventional dual-seal particle belts. Specifically, the particle belt of the present invention includes a separate zip-fastener type container disposed inside the individual cells of the belt, as well as a method for producing the belt.
Because the material is first filled into a zip-fastener type container, the material can be sufficiently sealed to prevent escape of particles and/or any cross contamination. Specifically, the process of the present invention includes sealing the zip fastener containers with the brass flake therein, prior to placing the zip-fastener containers in the belt. It is therefore possible to handle the sealed zip-fastener containers without risking leakage or contamination of the belt prior to heat-sealing thereof.
In order to overcome the problems associated with dry filling of the brass flake, the preset inventors have developed a procedure involving a slurry. The slurry generally contains a heterogeneous mixture of the particulate material and a liquid. Once the slurry is introduced into the containers, the slurry is dried, leaving the dry particulate behind.